Window and door problems, explained properly

A draught is usually a compression problem — gasket, hinge or seal — long before it's a reason to replace the window.

Rot in the bottom rail is repairable; rot that has reached the joints and the cill usually isn't worth chasing.

Handles are a cheap wearing part — the trick is matching spindle length, backset and screw centres so it fits first time.

Friction stays are consumable — when they corrode or bend, the sash drops out of square and everything else starts to fail with it.

Yellowing is cosmetic and treatable; splits at the welded corners are structural and aren't.

A door that needs lifting, shoving or a second attempt to lock is warning you before the gearbox fails completely.

A composite slab that catches on the frame has almost always moved at the hinges, and hinges are adjustable in three planes.

A sliding door that fights you is nearly always rollers and track debris, not a dead door.

Most break-ins through glazed openings exploit the cylinder or the keeps, both of which are upgradeable in an afternoon.

French doors are a pair, so the fault is usually in how the two leaves meet rather than in either leaf on its own.

Fog between the panes means the sealed unit has failed — the glass can usually be swapped without touching the frame.

Which face the water sits on tells you everything: inside is ventilation, between the panes is a failed unit, outside is normal physics.

Asymmetric glass thickness and a good frame seal cut traffic noise; simply adding a third identical pane often doesn't.

Most of the heat leaves through the roof and the frames, so that's where the money should go first.